<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

   <style>
    .box{
     display: table-cell;
     vertical-align: middle;
     text-align: center;
     height: 100vh;
     width: 100vh;


        
    }
    p{
       width: 200px;
       height: 200px;
       background-color: aqua;
    }
  
       
       
    

   </style>

<body>
    <div>
        <div class="box">
            <p>table-cell </p>
        </div>
    </div>
</body>
</html>